Packaging using natural antimicrobials may protect pork
Edible films containing plant antimicrobials are gaining in importance as potential treatments for extending product shelf life and reducing the risk of pathogen growth on contaminated food surfaces.
The authors of this study, scientists working in the College of Agriculture and Life Sciences in Korea, maintain that biodegradable films also provide barriers to moisture migration, oxygen transfer, lipid oxidation, and volatile flavours.
Spoilage bacteria
Spoilage in pork, they added, can be caused by pathogenic bacteria such as E. coli and Listeria, with L. monocytogenes proving a particular food safety problem as it can grow even at refrigeration temperatures.
Although research has been carried out previously into methods of reducing pathogens on sausages using inoculated edible Gelidium corneum (GC), which is a type of red algae, it was noted that the GC film had weak tensile strength, explained the researchers.
The scientists said they decided to add gelatine to the GC film combined with GFSE and GTE for this study to examine whether it would improve the physical property of the material and they examined the packaging’s effect on pork loins inoculated with E. coli 0157.H and L. Monocytogenes during storage.
Study details
The scientists said that the pork loins were cut into 10 gram slices, with E. coli 0157.Hand L. Monocytogenes cultures then spread on the meat surfaces; the initial inoculation levels of the E. coli 0157.Hand L. Monocytogenes in the pork loin samples were 5.16 and 4.80 log CFU/g, respectively.
The inoculated meat was then packed, they continued, in direct contact by GCG film containing GFSE (0.08 per cent) or GTE (2.80 per cent)
A control was also set up, with pork loins packed in GCG film without GFSE or GTE, and following this all the pork loins were stored at 4°C for ten days using a sterile polystyrene tray.
Results
The study showed that the populations of the pathogenic bacteria in the meat packed with the GCG film with GFSE or GTE significantly reduced during storage, compared to the control.
“The population of the bacteria in the control was 5.47 log CFU/g after ten days of storage, whereas the populations of the bacteria in the pork loins packed with the GCG film containing GFSE or GTE were 4.88 and 4.47 log CFU/g respectively,” said the authors.
Tests were also carried out to investigate the physical properties of the GCG film, with the researchers maintaining that the tensile strength and water vapour permeability attributes of the material proved better than those of the GC film evaluated in an earlier study.
Commenting on the study, the scientists said the results suggest that the GCG film containing GFSE or GTE has considerable potential for use in antimicrobial packaging for food products.
Source: Journal of Food Science Volume 74, Issue 1Published online ahead of print doi: 10.1111/j. 1750-3841.2008.00987.xTitle: Physical Properties of Gelidium corneum – Gelatin Blend Films Containing Grapefruit Seed Extract or Green Tea Extract and Its Application in the Packaging of Pork LoinsAuthors: Hong, Y.H.; Lim, O.G; Song, K.B.
